Occurrence of an accessory pancreatic duct in the sheep.

An accessory pancreatic duct was studied in 10 Dorset male sheep (5 to 12 months old) and in 7 sheep fetuses (crown-rump length, 63 to 200 mm). The duct was present in 9 of the 10 adult sheep examined. It could not be seen grossly, but in serial sections, an accessory duct with some pancreatic tissue was seen to pass distally from the main pancreatic mass ahead of the bile duct, enter the wall of the duodenum at the beginning of its descending portion, pass distally in the submucosa for about 10 mm, and then approach the mucosa. The wall of the duct acquired tubular mucous glands and was supported by muscle bundles during its intramural course. The sections from the sheep fetuses confirmed the presence of a patent accessory duct until it united with the duodenal mucosa. In the adult, the accessory duct and the accompanying pancreatic tissue and glands appeared functional. It could not be determined how much of the pancreas may be drained by the accessory duct.